textproduct: Quad Cities

KEY MESSAGES

- An isolated shower/storm is possible early this evening in our southern counties.

- Widespread showers and storms will move through the area Thursday into Friday. Some of these storms may be strong to severe, with a Level 1 of 5 risk of severe storms for eastern Iowa, west-central Illinois, and northeast Missouri.

- Pleasant weekend weather ahead!

SHORT TERM /THROUGH WEDNESDAY NIGHT/

Issued at 210 PM CDT Tue Apr 21 2026

While sunshine has been widespread over our CWA though 1 PM in nearly all areas, a weak front is moving southeast through the Midwest. A short wave just ahead of this fropa, is bringing a very narrow area of showers and storms mainly to southeast Wisconsin as of early afternoon. The accas clouds are found southwest of this convection, and extends down through southeast Iowa. With dry low levels, there is little if any surface CAPE available for storms today, but MUCAPE around 500 J/KG is available for any storm that fires. The steep mid level lapse rates, around 8.5C/KM will bring a low, but still possible threat (~10%) of storms through early evening along this boundary, which will be in our south this evening. Any thunderstorm would be capable of producing small hail given the cool air aloft. I do think most if not all of this activity will be east of our CWA this evening.

Lows tonight, with variable cloud cover are looking much more mild, with lower 50s north to upper 50s central and south. This milder night will set the stage for another mild Wednesday, with highs in the upper 70s to near 80. The dry weather with south winds will continue Wednesday night, with lows dropping to the upper 50s in most areas.

LONG TERM /THURSDAY THROUGH MONDAY/

Issued at 210 PM CDT Tue Apr 21 2026

Upper-level ridging across the upper Mississippi River Valley begins to break down Wednesday night as the next longwave trough sets up over the Rockies. Surface cyclogenesis over northeast Montana and a high pressure across the Southeast will support strong southerly flow and moisture advection across the entire CWA Thursday into Thursday night as the cold front approaches. Diffluent flow aloft, CVA at 500 mb, and the surface front will be primary sources of lift, but the displaced trough to the northwest will keep mid-level lapse rates at 7-8 C/km, limiting our SBCAPE values to 500-700 J/kg across eastern Iowa and northeast Missouri. Effective bulk shear is also expected to be weak at 25-35 knots. Combining these factors, the SPC has a marginal (1 out of 5) risk for damaging winds Thursday night as thunderstorms form along the cold front.

On Friday, the flow across the CONUS returns to zonal as two shortwaves over the Canadian Rockies merge, stalling the progression of the longwave trough. The weekend appears to be a nice one with highs in the upper 60s to mid 70s with mostly dry conditions through Sunday afternoon.

On Sunday, the next shortwave in the subtropical jet rotates into the southern Plains, spawning the next low pressure system near the Colorado-Kansas border at the left exit region of a 110-knot jet streak. There is uncertainty in the exact track of this mid-latitude cyclone as it moves to the northeast. This will have an influence on our severe weather risk Sunday night into Monday, but additional rain across the region is for certain. Once the front moves through Monday evening, dry and cold air advection will suppress PoPs on Tuesday.

AVIATION /18Z TAFS THROUGH 18Z WEDNESDAY/

Issued at 1253 PM CDT Tue Apr 21 2026

General VFR conditions expected through the entire 24-hour period. A weak cold front will provide a SW-NE wind shift this evening with light winds at KCID and KDBQ. Further south, a few clouds and rain showers may develop around KBRL this afternoon into evening,but VFR conditions should persist. Cloud ceilings could drop below 3000 feet tomorrow morning around the front with coverage of FEW to SCT.

DVN WATCHES/WARNINGS/ADVISORIES

IA...None. IL...None. MO...None.